A three-stage magnetic suspension centrifugal compressor unit system

Abstract

The utility model discloses a kind of three-stage magnetic suspension centrifugal compressor unit systems, it is related to air compressor technical field, including one two-stage compression unit and three-stage compression unit, the air inlet pipe is provided at the first-stage air inlet of one two-stage compression unit, the air path of the first-stage exhaust and two-stage air inlet of one two-stage compression unit is provided with first-stage interstage cooler, and the exhaust port of first-stage interstage cooler is connected with the two-stage air inlet of one two-stage compression unit by two-stage air inlet pipe, the air path of the two-stage exhaust of one two-stage compression unit and the three-stage air inlet of three-stage compression unit is provided with two-stage cooler. The utility model significantly reduces operating noise and mechanical loss from the root, cooperate three-stage air compression and first-stage interstage cooler, two-stage cooler constitute near isothermal process, greatly improve compression efficiency, realize efficient energy saving, while completely abandon lubricating oil system, ensure that the final output compressed air is clean and oil-free.

Description

Technical Field

[0001] This utility model relates to the field of air compressor technology, specifically a three-stage magnetic levitation centrifugal compressor unit system. Background Technology

[0002] As an indispensable general-purpose equipment in industrial production, air compressors provide clean and stable compressed air for various pneumatic tools, processes and automation systems. Their technological development and performance improvement are of great significance for ensuring production continuity, improving energy efficiency and reducing operating costs.

[0003] Among existing air compressor technologies, oil-injected screw air compressors have been widely and long-term used due to their advantages such as wide operating pressure range, mature technology, and relatively low initial purchase cost. This type of compressor lubricates the compression chamber by injecting lubricating oil and plays a major role in supplying air in many industrial applications, forming an important foundation of current compressed air systems.

[0004] However, existing technologies still have shortcomings in use: traditional oil-injected screw air compressors typically have high operating noise due to mechanical contact and friction during operation. Their compression process is accompanied by high mechanical and flow losses, resulting in high overall energy consumption. More importantly, to ensure operational reliability, they must rely on a lubrication system, thus requiring regular replacement of the entire machine's lubricating oil, as well as maintenance and replacement of components such as oil filters and oil separators. This not only increases continuous maintenance costs and downtime but also inevitably introduces oil into the compressed air, making it difficult to meet the demand for oil-free, clean compressed air in fields with stringent air quality requirements, such as food and pharmaceutical industries. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the existing defects and provide a three-stage magnetic levitation centrifugal compressor unit system, which significantly reduces operating noise and mechanical losses from the source. With the near isothermal process formed by the three-stage air compression, the first-stage intercooler, and the second-stage cooler, the compression efficiency is greatly improved, achieving high efficiency and energy saving. At the same time, the lubrication system is completely eliminated, ensuring that the final output compressed air is clean and oil-free, which can effectively solve the problems in the background technology.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a three-stage magnetic levitation centrifugal compressor unit system, comprising a primary and secondary compression unit and a tertiary compression unit. An intake duct is provided at the primary air inlet of the primary and secondary compression units. A primary interstage cooler is provided on the air path of the primary exhaust and secondary intake of the primary and secondary compression units, and the exhaust port of the primary interstage cooler is connected to the secondary air inlet of the primary and secondary compression units via a secondary air inlet pipe. A secondary cooler is provided on the air path of the secondary exhaust of the primary and secondary compression units and the tertiary intake of the tertiary compression unit. An exhaust pipe is provided at the tertiary exhaust port of the tertiary compression unit. All three compression units employ magnetic levitation centrifugal compressors. Coolant channels are provided on both the first and second stage compression units. The coolant channels of the first and second stage compression units are connected to the first coolant circulation loop unit, and the coolant channels of the third stage compression unit are connected to the second coolant circulation loop unit. Cooling water channels are provided inside both the first-stage intercooler and the second-stage cooler. The inlet ends of the cooling water channels inside the first-stage intercooler and the second-stage cooler are connected to the main inlet pipe through distribution pipes, and the outlet ends of the cooling water channels inside the first-stage intercooler and the second-stage cooler are connected to the main outlet pipe through distribution pipes.External air first enters the first-stage compression section of the primary and secondary compression units through the intake duct for initial compression. The resulting high-temperature gas is then introduced into the first-stage interstage cooler for cooling. The cooled gas then enters the second-stage compression section of the primary and secondary compression units through the second-stage intake pipe for a second pressurization, followed by further cooling through the second-stage cooler. Finally, the gas, after two compressions and cooling cycles, enters the tertiary compression unit for the final pressure boost and is supplied to the air-consuming equipment through the exhaust pipe. Throughout the compression path, the cooling water channels of the first-stage and second-stage interstage coolers, used to cool the compressed air, are supplied by the same external circulating water system through the main inlet pipe and returned through the main outlet pipe. Simultaneously, both the primary, secondary, and tertiary compression units employ magnetic levitation centrifugal compressors. The magnetic levitation bearings inside the magnetic levitation centrifugal compressors utilize magnetic force to control the rotor. The magnetic levitation system enables contactless and frictionless operation, resulting in low noise and significantly reduced mechanical losses. It also allows the rotor to operate stably at extremely high speeds, greatly improving compression efficiency and achieving significant energy savings. Contactless operation also means almost no bearing wear, extending the theoretical lifespan and operational reliability of the compressor to far exceed that of traditional mechanical bearing compressors. The full magnetic levitation system fundamentally eliminates the need for a lubrication system, completely eliminating the tedious maintenance work and costs associated with regularly changing the entire machine's lubricating oil, oil filters, and oil separators. This achieves truly maintenance-free and oil-free operation, producing clean, oil-free compressed air. Independent first and second coolant circulation loop units provide efficient and precise cooling for their respective magnetic levitation centrifugal compressor units, further ensuring the high efficiency and stability of the magnetic levitation centrifugal compressor unit and preventing performance degradation caused by uneven or insufficient cooling.

[0007] Furthermore, the primary and secondary compression units are primary and secondary main units. The primary air inlet of the primary and secondary main units is equipped with a primary impeller that mates with the air inlet duct, and the secondary air inlet of the primary and secondary main units is equipped with a secondary impeller that mates with the secondary air inlet pipe. The secondary exhaust port of the primary and secondary main units is connected to the air inlet of the secondary cooler via a secondary exhaust pipe. The input terminal of the primary and secondary main units is electrically connected to the output terminal of inverter one. The primary and secondary main units are driven by an independent inverter one. The primary and secondary main units integrate the primary and secondary impellers for secondary compression, resulting in a compact structure, high integration, and small size.

[0008] Furthermore, the three-stage compression unit is a three-stage main unit. The three-stage main unit has a three-stage intake pipe at its three-stage intake port that connects to the exhaust port of the two-stage cooler. A three-stage impeller, cooperating with the three-stage intake pipe, is also located at the three-stage intake port of the main unit. The exhaust port of the main unit is connected to the exhaust pipe. The input terminal of the main unit is electrically connected to the output terminal of inverter two. The three-stage main unit is driven by an independent inverter two.

[0009] Furthermore, the first coolant circulation loop unit includes a water tank, a centrifugal water pump, and a cooler. The cooler has internal cooling water channels and coolant flow channels. The inlet of the cooling water channel of the cooler is connected to the main inlet pipe through a branch pipe, and the outlet of the cooling water channel of the cooler is connected to the main drain pipe through a branch pipe. The outlet of the water tank is connected to the suction port of the centrifugal water pump. The discharge port of the centrifugal water pump is connected to the inlet of the coolant flow channel inside the cooler through a branch pipe. The discharge port of the coolant flow channel inside the cooler is connected to the coolant flow channels on the inverter and the primary and secondary main units through different branches. The discharge ports of the coolant flow channels on the inverter and the primary and secondary main units are connected to the water tank through branch pipes. The coolant is pumped out of the water tank by the centrifugal water pump and first enters the coolant flow channel of the cooler. Here, it exchanges heat with the external cooling water from the main water inlet pipe through the partition wall and is cooled down. The cooled coolant is divided into two paths and flows through the coolant flow channels inside the inverter and the first and second stage main unit, respectively, to absorb the heat generated by them. Finally, it flows back to the water tank with heat, completing a closed loop.

[0010] Furthermore, the second coolant circulation loop unit includes a water tank, a second centrifugal water pump, and a second cooler. The second cooler has internal cooling water channels and coolant flow channels. The inlet of the cooling water channel of the second cooler is connected to the main inlet pipe via a branch pipe, and the outlet of the cooling water channel of the second cooler is connected to the main drain pipe via a branch pipe. The outlet of the water tank is connected to the suction port of the second centrifugal water pump, and the discharge port of the second centrifugal water pump is connected to the inlet of the coolant flow channel inside the second cooler via a branch pipe. The discharge port of the coolant flow channel inside the second cooler is connected to the coolant flow channels on the second and third stage inverters via different branches, and the discharge ports of the coolant flow channels on the second and third stage inverters are connected to the water tank via branch pipes. The coolant is pumped from the water tank by the second centrifugal water pump, cooled by the second cooler, and then distributed to the second and third stage inverters for heat absorption before finally returning to the water tank.

[0011] Furthermore, an air intake filter is provided at the air intake end of the air intake duct. This filter removes dust and particulate matter from the intake air.

[0012] Furthermore, the exhaust pipe is equipped with a vent valve and a regulating valve, which are connected and communicate with the interior of the exhaust pipe. The vent valve is used for rapid pressure relief to prevent overpressure, while the regulating valve is used for precise control of the relief amount to stabilize the output pressure. Together, they prevent the compressor from surging, ensuring stable gas supply and equipment safety.

[0013] Furthermore, a first drain valve is installed at the condensate drain outlet of the first-stage intercooler, and a second drain valve is installed at the condensate drain outlet of the second-stage cooler. This automatically and promptly drains the condensate that precipitates during the compressed air cooling process.

[0014] Based on the above technical solution, the beneficial effects of this utility model's three-stage magnetic levitation centrifugal compressor unit system after practical application are as follows: 1. In this utility model, both the first and second stage main units and the third stage main unit adopt magnetic levitation centrifugal compressor main units. The internal magnetic levitation bearings realize contactless and frictionless operation of the rotor, which significantly reduces operating noise and mechanical loss from the source. Combined with the near isothermal process formed by the three-stage air compression, the first-stage intercooler, and the second-stage cooler, the compression efficiency is greatly improved, achieving high efficiency and energy saving. At the same time, the oil-free design completely eliminates the lubrication system, so that the first and second stage main units and the third stage main unit do not require any lubrication. The intake filter ensures clean intake air. The compressed gas flows through the intake duct, each stage impeller, the second-stage intake pipe, the second-stage exhaust pipe, the third-stage intake pipe, and all the way to the exhaust pipe without oil contamination. This not only completely eliminates the tedious maintenance work and costs of replacing lubricating oil, oil filters, oil separators, etc., achieving true maintenance-free operation, but also ensures that the final output compressed air is clean and oil-free, which can meet the highest requirements for clean compressed air in the food, pharmaceutical and other fields.

[0015] 2. This utility model uses the first coolant circulation loop unit and the second coolant circulation loop unit to independently and accurately control the temperature of the first-stage and second-stage main units and the third-stage main unit, respectively, to avoid performance degradation. With the help of the vent valve and regulating valve on the exhaust pipe for anti-surge adjustment, the system's reliability, stability and long service life under high load are fully ensured. Attached Figure Description

[0016] Figure 1 This is a front-view three-dimensional structural diagram of the gas path system of this utility model.

[0017] Figure 2 This is a front-view three-dimensional structural diagram of the water system in this utility model.

[0018] Figure 3 This is a schematic diagram of the control flow structure of this utility model.

[0019] In the diagram: 1-Intake filter, 2-Intake duct, 3-First and second stage main units, 4-First stage impeller, 5-First stage interstage cooler, 6-Second stage intake pipe, 7-Second stage impeller, 8-Second stage exhaust pipe, 9-Second stage cooler, 10-Third stage intake pipe, 11-Third stage main unit, 12-Third stage impeller, 13-Exhaust pipe, 14-Vent valve, 15-Regulating valve, 16-Main water inlet pipe, 17-Main drain pipe, 18-Variable frequency drive one, 19-Variable frequency drive two, 20-Centrifugal water pump one, 21-Centrifugal water pump two, 22-Cooler one, 23-Cooler two, 24-Drain valve one, 25-Drain valve two, 26-Water tank. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Please see Figure 1-3This embodiment provides a technical solution: a three-stage magnetic levitation centrifugal compressor unit system, including a first-stage compression unit, a second-stage compression unit, and a third-stage compression unit. An intake duct 2 is provided at the first-stage inlet of the first-stage compression unit. A first-stage interstage cooler 5 is provided on the air path of the first-stage exhaust and second-stage intake of the first-stage compression unit, and the exhaust port of the first-stage interstage cooler 5 is connected to the second-stage inlet of the first-stage compression unit via a second-stage intake pipe 6. A second-stage cooler 9 is provided on the air path of the second-stage exhaust of the first-stage compression unit and the third-stage intake of the third-stage compression unit. An exhaust pipe 13 is provided at the third-stage exhaust port of the third-stage compression unit. The unit adopts a magnetic levitation centrifugal compressor host. Coolant channels are provided on the first-stage, second-stage, and third-stage compression units. The coolant channels of the first-stage and second-stage compression units are connected to the first coolant circulation loop unit, and the coolant channels of the third-stage compression unit are connected to the second coolant circulation loop unit. Cooling water channels are provided inside the first-stage intercooler 5 and the second-stage cooler 9. The inlet ends of the cooling water channels inside the first-stage intercooler 5 and the second-stage cooler 9 are connected to the main inlet pipe 16 through the water distribution pipes. The outlet ends of the cooling water channels inside the first-stage intercooler 5 and the second-stage cooler 9 are connected to the main drain pipe 17 through the water distribution pipes.External air first enters the first-stage compression section of the first- and second-stage compression units via intake duct 2 for initial compression. The resulting high-temperature gas is then introduced into the first-stage interstage cooler 5 for cooling. The cooled gas then enters the second-stage compression section of the first- and second-stage compression units via the second-stage intake pipe 6 for a second pressurization. Subsequently, it flows through the second-stage cooler 9 for further cooling. Finally, the gas, after two compressions and coolings, enters the third-stage compression unit to complete the final pressure increase and is supplied to the air-consuming equipment via exhaust pipe 13. Throughout the compression path, the cooling water channels of the first-stage interstage cooler 5 and the second-stage cooler 9, used to cool the compressed air, are supplied with water from the same external circulating water system through the main inlet pipe 16 and returned through the main drain pipe 17. Simultaneously, both the first-, second-stage, and third-stage compression units employ magnetic levitation centrifugal compressors. The magnetic levitation bearings inside the magnetic levitation centrifugal compressors are entirely... Magnetic force supports the rotor, enabling contactless and frictionless operation with low noise and significantly reduced mechanical losses. It also allows the rotor to operate stably at extremely high speeds, greatly improving compression efficiency and achieving significant energy savings. Contactless operation also means almost no bearing wear, resulting in a theoretical lifespan and operational reliability far exceeding that of traditional mechanical bearing compressors. Full magnetic levitation fundamentally eliminates the lubrication system, completely eliminating the tedious maintenance work and costs of regularly changing the entire machine's lubricating oil, oil filters, and oil separators. This achieves truly maintenance-free and oil-free operation, producing clean, oil-free compressed air. Independent first and second coolant circulation loop units provide efficient and precise cooling for their respective magnetic levitation centrifugal compressor units, further ensuring the high efficiency and stability of the magnetic levitation centrifugal compressor units and preventing performance degradation caused by uneven or insufficient cooling.

[0022] Furthermore, the primary and secondary compression units are primary and secondary compressor units 3. The primary intake port of the primary compressor unit 3 is equipped with a primary impeller 4 that mates with the intake duct 2, and the secondary intake port of the primary and secondary compressor unit 3 is equipped with a secondary impeller 7 that mates with the secondary intake pipe 6. The secondary exhaust port of the primary and secondary compressor unit 3 is connected to the intake port of the secondary cooler 9 via a secondary exhaust pipe 8. The input terminal of the primary and secondary compressor unit 3 is electrically connected to the output terminal of the frequency converter 18. The primary and secondary compressor unit 3 is driven by an independent frequency converter 18. The primary and secondary compressor unit 3 integrates the primary impeller 4 and the secondary impeller 7 for secondary compression, resulting in a compact structure, high integration, and small size.

[0023] Furthermore, the three-stage compression unit is a three-stage compressor 11. The three-stage compressor 11 has a three-stage intake pipe 10 connected to the exhaust port of the two-stage cooler 9 at its three-stage intake port. A three-stage impeller 12, which mates with the three-stage intake pipe 10, is also located at the three-stage intake port of the compressor 11. The exhaust port of the compressor 11 is connected to an exhaust pipe 13. The input terminal of the compressor 11 is electrically connected to the output terminal of the second frequency converter 19. The three-stage compressor 11 is driven by an independent second frequency converter 19.

[0024] Furthermore, the first coolant circulation loop unit includes a water tank 26, a centrifugal water pump 20, and a cooler 22. The cooler 22 is internally equipped with cooling water channels and coolant flow channels. The inlet of the cooling water channel of the cooler 22 is connected to the main inlet pipe 16 through a branch pipe, and the outlet of the cooling water channel of the cooler 22 is connected to the main drain pipe 17 through a branch pipe. The outlet of the water tank 26 is connected to the suction port of the centrifugal water pump 20. The outlet of the centrifugal water pump 20 is connected to the inlet of the coolant flow channel inside the cooler 22 through a branch pipe. The outlet of the coolant flow channel inside the cooler 22 is connected to the coolant flow channels on the inverter 18 and the first and second stage main unit 3 through different branches, and the outlets of the coolant flow channels on the inverter 18 and the first and second stage main unit 3 are connected to the water tank 26 through a branch pipe. The coolant is pumped out from the water tank 26 by the centrifugal water pump 20 and first enters the coolant flow channel of the cooler 22. Here, it exchanges heat with the external cooling water from the main water inlet pipe 16 through the partition wall and is cooled down. The cooled coolant is divided into two paths and flows through the coolant flow channels inside the inverter 18 and the first and second stage main unit 3, respectively, to absorb the heat generated by them. Finally, it flows back to the water tank 26 with heat, completing a closed loop.

[0025] Furthermore, the second coolant circulation loop unit includes a water tank 26, a centrifugal water pump 21, and a cooler 23. The cooler 23 has cooling water channels and coolant flow channels inside. The inlet of the cooling water channel of the cooler 23 is connected to the main inlet pipe 16 through a branch pipe, and the outlet of the cooling water channel of the cooler 23 is connected to the main drain pipe 17 through a branch pipe. The outlet of the water tank 26 is connected to the suction port of the centrifugal water pump 21. The outlet of the centrifugal water pump 21 is connected to the inlet of the coolant flow channel inside the cooler 23 through a branch pipe. The outlet of the coolant flow channel inside the cooler 23 is connected to the coolant flow channels on the inverter 2 19 and the third-stage host 11 through different branches. The outlets of the coolant flow channels on the inverter 2 19 and the third-stage host 11 are connected to the water tank 26 through a branch pipe. The coolant is pumped out from the water tank 26 by the centrifugal water pump 21, cooled by the cooler 23, and then distributed to the frequency converter 2 19 and the three-stage host 11 for heat absorption, and finally returned to the water tank 26.

[0026] Furthermore, an air intake filter 1 is provided at the air intake end of the air intake duct 2. This filter removes dust and particulate matter from the intake air.

[0027] Furthermore, the exhaust pipe 13 is equipped with a vent valve 14 and a regulating valve 15, and the vent valve 14 and the regulating valve 15 are connected and communicate with the interior of the exhaust pipe 13. The vent valve 14 is used for rapid pressure relief to prevent overpressure, and the regulating valve 15 is used for precise control of the relief amount to stabilize the output pressure, and together they prevent the compressor from surging, ensuring stable gas supply and equipment safety.

[0028] Furthermore, a drain valve 24 is installed at the condensate drain outlet of the primary intercooler 5, and a drain valve 25 is installed at the condensate drain outlet of the secondary cooler 9. This automatically and promptly drains the condensate that precipitates during the compressed air cooling process.

[0029] The working principle of the three-stage magnetic levitation centrifugal compressor unit system provided by this utility model is as follows: In operation, external air first enters the primary compression section of the first- and second-stage compressor 3 via the intake duct 2 for initial compression. The resulting high-temperature gas is then introduced into the primary interstage cooler 5 for cooling. The cooled gas then enters the secondary compression section of the first- and second-stage compressor 3 via the secondary intake pipe 6 for a second pressurization, and then flows through the secondary cooler 9 for further cooling. Finally, the gas, after two compressions and coolings, enters the tertiary compressor 11 to complete the final pressure boost and is supplied to the air-consuming equipment via the exhaust pipe 13. Throughout the compression path, the cooling water channels of the primary interstage cooler 5 and the secondary cooler 9, used for cooling the compressed air, are supplied by the same external circulating water system through the main inlet pipe 16 and returned through the main drain pipe 17. Simultaneously, both the first- and second-stage compressors 3 and the tertiary compressor 11 employ magnetic levitation centrifugal compressors. The magnetic levitation bearings inside the magnetic levitation centrifugal compressors are fully integrated... The rotor is supported by magnetic force, achieving contactless and frictionless operation with low noise and significantly reduced mechanical losses. It also allows the rotor to operate stably at extremely high speeds, greatly improving compression efficiency and resulting in significant energy savings. Contactless operation also means almost no bearing wear, extending the theoretical lifespan and operational reliability of the compressor to far exceed that of traditional mechanical bearing compressors. Full magnetic levitation fundamentally eliminates the lubrication system, completely eliminating the tedious maintenance work and costs associated with periodically changing the entire machine's lubricating oil, oil filters, and oil separators. This achieves truly maintenance-free and oil-free operation, producing clean, oil-free compressed air. Independent first and second coolant circulation loop units provide efficient and precise cooling for their respective magnetic levitation centrifugal compressor units, further ensuring the high efficiency and stability of the magnetic levitation centrifugal compressor units and preventing performance degradation caused by uneven or insufficient cooling.

[0030] The above description is merely an embodiment of this utility model and does not limit the scope of this utility model. Any equivalent structural or procedural transformations made based on the description and drawings of this utility model, or direct or indirect applications in other related technical fields, are similarly included within the protection scope of this utility model.

Claims

1. A three-stage magnetic levitation centrifugal compressor unit system, comprising a primary and secondary compression unit and a tertiary compression unit, wherein an intake duct is provided at the primary air inlet of the primary and secondary compression units, a primary interstage cooler is provided on the air path of the primary exhaust and secondary intake of the primary and secondary compression units, and the exhaust port of the primary interstage cooler is connected to the secondary air inlet of the primary and secondary compression units via a secondary air inlet pipe, a secondary cooler is provided on the air path of the secondary exhaust of the primary and secondary compression units and the tertiary intake of the tertiary compression unit, and an exhaust pipe is provided at the tertiary exhaust port of the tertiary compression unit, characterized in that: The first, second, and third stage compression units all employ magnetic levitation centrifugal compressors. Each of these units has a coolant flow channel. The coolant flow channels of the first and second stage compression units are connected to the first coolant circulation loop unit, and the coolant flow channels of the third stage compression unit are connected to the second coolant circulation loop unit. Both the first-stage intercooler and the second-stage cooler have internal cooling water channels. The inlet ends of the cooling water channels in both the first-stage intercooler and the second-stage cooler are connected to the main inlet pipe via branch pipes, and the outlet ends of the cooling water channels in both the first-stage intercooler and the second-stage cooler are connected to the main drain pipe via branch pipes.

2. The three-stage magnetic levitation centrifugal compressor unit system according to claim 1, characterized in that: The primary and secondary compression units are primary and secondary main units. The primary air inlet of the primary and secondary main units is equipped with a primary impeller that cooperates with the air inlet duct. The secondary air inlet of the primary and secondary main units is equipped with a secondary impeller that cooperates with the secondary air inlet pipe. The secondary exhaust port of the primary and secondary main units is connected to the air inlet of the secondary cooler through the secondary exhaust pipe. The input terminal of the primary and secondary main units is electrically connected to the output terminal of the inverter.

3. The three-stage magnetic levitation centrifugal compressor unit system according to claim 2, characterized in that: The three-stage compression unit is a three-stage main unit. The three-stage main unit has a three-stage air intake port that is connected to the exhaust port of the two-stage cooler. The three-stage main unit has a three-stage impeller that cooperates with the three-stage air intake port. The exhaust port of the three-stage main unit is connected to the exhaust pipe. The input terminal of the three-stage main unit is electrically connected to the output terminal of the second frequency converter.

4. The three-stage magnetic levitation centrifugal compressor unit system according to claim 2, characterized in that: The first coolant circulation loop unit includes a water tank, a centrifugal water pump, and a cooler. The cooler has internal cooling water channels and coolant flow channels. The inlet of the cooling water channel of the cooler is connected to the main inlet pipe through a branch pipe, and the outlet of the cooling water channel of the cooler is connected to the main drain pipe through a branch pipe. The outlet of the water tank is connected to the suction port of the centrifugal water pump. The outlet of the centrifugal water pump is connected to the inlet of the coolant flow channel inside the cooler through a branch pipe. The outlet of the coolant flow channel inside the cooler is connected to the coolant flow channels of the inverter and the primary and secondary main units through different branches. The outlets of the coolant flow channels of the inverter and the primary and secondary main units are connected to the water tank through branch pipes.

5. The three-stage magnetic levitation centrifugal compressor unit system according to claim 3, characterized in that: The second coolant circulation loop unit includes a water tank, a second centrifugal water pump, and a second cooler. The second cooler has cooling water channels and coolant flow channels inside. The inlet of the cooling water channel of the second cooler is connected to the main inlet pipe through a branch pipe, and the outlet of the cooling water channel of the second cooler is connected to the main drain pipe through a branch pipe. The outlet of the water tank is connected to the suction port of the second centrifugal water pump. The discharge port of the second centrifugal water pump is connected to the inlet of the coolant flow channel inside the second cooler through a branch pipe. The discharge port of the coolant flow channel inside the second cooler is connected to the coolant flow channels on the second and third stage inverters through different branches, and the discharge ports of the coolant flow channels on the second and third stage inverters are connected to the water tank through branch pipes.

6. The three-stage magnetic levitation centrifugal compressor unit system according to any one of claims 1 to 5, characterized in that: An air intake filter is provided at the air intake end of the air intake duct.

7. The three-stage magnetic levitation centrifugal compressor unit system according to any one of claims 1 to 5, characterized in that: The exhaust pipe is equipped with a vent valve and a regulating valve, and the vent valve and the regulating valve are connected to the inside of the exhaust pipe.

8. The three-stage magnetic levitation centrifugal compressor unit system according to any one of claims 1 to 5, characterized in that: A drain valve is installed at the condensate drain outlet of the primary interstage cooler, and a drain valve is installed at the condensate drain outlet of the secondary cooler.

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